If you read it as a sequel, the narrative will disappoint you. There is not much to tell about Francesca, neither is Kincaid's passion towards the Iowa farmer's wife. There is a brief description on the lovers' almost re-encounter on the Roseman Bridge, the trysting place where the romance begins 16 years ago, yet the author never states whether the truck she heard up the hill is Kincaid's Harry(his car's name) heading away. Not knowing and afraid of what would happen when they meet again, the photographer has come to say adieu to his once and only great love, which is epitomized by the bridge.
The author does confirm that between Kincaid and Francesca great love has occurred though in his description, both are not certain whether the feeling sustains in the other's heart after all those years. Yet this is where the suspense lies. In the later years of Kincaid's life, he suddenly comes across a 'son' and a woman he has made love to forty years ago (which is the main part of this story). A new kind of emotion is stirred up, and he is thus filled with guilt and care. He confesses to Carlisle that he has not loved his mother back then (when free love prevails after war), and he instructs Carlisle to burn all his work, including Francesca's photos, for he wants no traces of his life in this world after death.
The author seems to hint at the end, that Kincaid, after meeting his son, desires to take back the will of sending all his personal properties to Francesca. But busying with seeing Carlisle and the mother, he is prevented to do so and dying of heart attack leaves his cameras and the old photos eventually at Francesca's hand. This has already been told in The Bridges of the Madison County but we do not know the details lying in between.
It is thus interesting, as a work of fiction, this two-part romance manifests itself in the form of research work prying into the real life of real people. So what else between Kincaid and Francesca? This is not we should ask about as we would on some simple melodramas. This is what life seems to be. Francesca loves Kincaid to the end but it MAY not be true in reverse. But it is this 'maybe' that gives life so much mystery and secret sparks that shine in the dark, as are stars that shine in our heart, at some epiphany moments for us to remember all through our lives.
photo from http://www.rosemanbridge.com/